Composite ringing apparatus.



J. F. TOOMEY.

COMPOSITE RINGING APPARATUS.

APPLxcATloN HLED 00T. 3o, |917.

ATTORNEY Patented Jan. 7,1919.

2 SHEETS-SHEET 2.

IlllllrllllllllnllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllJ. F. TOOMEY.

COMPOSITE HANGING APPARATUS.

APPLICATION FILED OCT. 30. 1917.

UNITED STATES APATEOFFIC. j

JOHN F. TOOMEY, or NEW YORK, N. Y., AssrGNon ro AMERICAN TELEPHONE ANDTELEGRAPH COMPANY, A oonronATIoN or NEW YORK.

COMPOSITE RINGING APPARATUS.

Specification of Letters Patent.

Patented Jan. 7, 1919.

Application led October 30, 1917. Serial No. 199,317.

To all whom t may concern: Y

Be it lmown that I, JOHN F. Tommi?, residing at New York, in the Icountyof New York and State of New York, have invented certain Improvements inComposite Ringing Apparatus, of which the following is a specification.

This invention relates to ringing apparatus and more particularly toringing apparatus for use in connection with composited telephoneI andtelegraph lines.

It is'one of the objects of the invention to provide an arrangementwhereby the frequency of the ringing current coming in over atransmission line may be translated into a frequency better adapted foruse in operating the customary ringing apparatus associated with aswitchboard. A further object is to provide means whereby the frequencyof the ringing current commonly 1used at the switchboard may betranslated into a frequency better adapted to be sent out over atransmission line. Al further object of the invention is to provide acomposite ringing apparatus which may be disconnected from the line whenthe ringer is not required and better transmission is desired fortalking purposes. Another object consists in the provision of meanswhereby the marginal relays of the composite ringing set may be testedand adjusted. Further objects of the invention will be clear from thedetailed description to be given later.

Then a transmission line is used solely for telephone purposes theringing current transmitted thereover may be of a frequency in theneighborhood of 16 cycles, and the ringing apparatus at theswitchboardis constructed to generate and to respond to currents of approximatelythis frequency. When, however, the transmission line is composited andused for both telephone and telegraph purposes, it has been found thatringing currents having a frequency of the order above mentioned can notbe transmitted out over such a line from the switchboard, nor can theybe transmitted over such a line to the switchboard. This' is because thefrequency of these ringing currents is approximately the same as thefrequency of the currents used for telegraphic purposes, and the filteror apparatus devised to keep these telegraphic currents from enteringand interfering with the telephone apparatus,

also servesto attenuate and practically extinguish these ringingcurrents of similar frequency. Accordingly, the ringing current tobewell adapted for use over a composited transmission line must be of afrequency above the limit shut out by this filter, and it has been foundthat a` ringing current having a frequency in the neighborhood of 133cycles is well adapted for ,use over such a transmission line, althoughany frequency above theA limit of this filter may be satisfactory.

In order to change the low frequency ringing current Generated at theswitchboard into a higher irequency ringing current suitable for useover the transmission line and vice versa, arrangements are employedknown as composite ringing sets. Such sets include suitable switchingmeans for associating the apparatus with the transmission line, and aplurality of marginal relays. One type of these marginal relays isadjusted to respond only to the ringing current coming in overv thetransmission line and its actuation serves to connect to the conductorsleading to the switchboard apparatus a local-source of ringing currentsuitable to operate such apparatus. The other type kof marginal relay isadjusted to respond only to ringing current impressed on the line at theswitchboard and its actuation serves to connect to the outgoingtransmission line a source of ringing current suitablefor use thereover.In former types'of composite ringing sets the switching means forassociating the set with the transmission line have usually beenincluded serially in the line and this has often served.-

to impair the quality of the transmission for talking purposes.L In thecomposite set embodied in the present invention these switching meansare associated with the transmission line by means of conductors bridgedin shunt across the line'and by the operation of these means thecomposite set may be entirely disconnected from the line and the qualityof the transmission be improved for talking purposes. Further it hasbeen found that the type of marginal relay used in such composite sets,requires delicate adjustment so that only currents of a desiredfrequency will cause it to operate. Accordingly the arrangements of thisinvention comprise means .for testing and adjusting such relays and alsoinclude-suitable switching means whereby, when one of these relaysbecomes out of order, other relays of a similar type may be substituedtherefor.

The invention may now be more fully understood by reference to theaccompanying drawing, the Figures l and 2 of which when taken togetherillustrate diagramma-tically the preferred form of the invention. In theFig. l the incoming porti-on of a transmission line Ll is shownconnected by means of conductors 3 and e to the conductors 8O leading tothe telephone switchboard. The apparatus of the composite ringer set islassociated with the transmission line by means of the conductors 5which are bridgedA in shunt across the conductors 3 andslfand terminatein the jack J2. Leading from the jacked2 and terminating in the jack J:are: the conductors T and S. Associatedwith these conductors is theretardation. coilelQ adapted to render the composite ringerset lofhighimpedance to telephone currents. vBridged across these conductors 7 and8 is. the inarginal relay (3, which is adjusted to respond only toringing current of a. frequency similar to that of the current atthetelephone switchboard, andwhieh may in practicebe 16 cycles.Accordingly they ringing current sent out from the switchboard over theconductors SOwill cause the relay 6 to;y operate. The operation .of thislrelay-.serves toclose a circuit through ther-clays land l and cause-Sthem to operate. The functioning' of relay l disconnects they lineL1from the.y conductors 3 and 4 and connects the line to the conductors 2lleading to the apparatus'l. The apparatus 3l serves to generate ringingcurrent having a, frequency suitable for use @ver the transmission lineL which =may in practico -bc 133 cycles. The apparatus 31 is caused tooperate by thefunctioning of the above. mentioned relay 10. Accordinglythe ringing current sent out fromthe switchboard causes, by the.operation of these relays, the apparatus 3l to .send out over the lineL, by means of the conductors 21 a ringing current having a frequencysuitable for transmission over such a' composited transmission line.

Normally connected to the jack J is the jack J6 from the contacts ofwhich are shown the conductors 22, 23, and 2i, leading to the marginalrelay 29. T his marginal rela-y is adjusted to respond only to ringinglcurrent haring a frequency similar to thatof the ringing currenttransmittedover the transmission line L1, which fin practice might be133 cycles. The energization of the marginal relay 29 by the ringingcurrent coming in over the line L1 causes its armature te retract andbreaks the no 'mally closed circuit through the relay ll. 'Thedenergization ofvv this relay operatesato closefav circuit through therelay' 2 bymeanso'f which'thc conductors 80 leading to the telephoneswitchboard are disconnected from the conductors I?) and 4 and connectedto a local source 2S of ringing current having a frequency suitable foroperating the telephone apparatus `at the switchboard.

A. second composite ringing set is shown including a. marginal relay 30similar in type to the marginal relay 29 and associated with a-.jaclr J4by the conductors 25, 2G, and 27. The jack Jr,L is connected to the jackJ3 and said jack is connected in turn to a jack J1 whereby the compositeringing set may be associated with another i transmission line.

This composite ringing set is `of the same type as the one associ-ated.with the ti nsmlsslon. line Ll and 11i-practice a 4number ot suchcomposite sets may be so arranged that Vall of their jacks willterminate at one test In order to test and adjust the marginalrelays ofthe type of relays 29 and 3Q, vapparatus is provided including a plug,P2 adapted to be inserted in the jacks JG or L or other jacksrel-ating` to the relay to kbe tested. From the tip and ring contacts of.plug P2 are conductors leading to the generating apparatus 3lheretofore mentioned. Includedv in` these conductors is an artificialline adapted to simulate the impedance of the transmission line Ll, saidartificial line comprising the resistances 32, 33, 34e and 55,theresista-nces 34C and 35 being bridged across thev mid-'points ofresistanccs 32 a nd 33. Associated rwith the resistance 35 is a shortcircuit under the control of the marginal relay 38 to be `hereinafterdescribed. From the sleeve contact of plug P2 is a conductor leading tothe rela)- 40 -which controls the test signal G0 in ay manner to behereinafter described. At. the test board and also at the racks ywhe-rethe marginal relays are located and which in practice ma)` be remotefrom the jacks at the test board are proi'ided multiple jacks J7 and (L,so arranged as to be easily accessible from any apparatusassociated-'with the composite ringers` portable control set comprisingthe lkeys l, and K2: the signal lamp (i0, the stance f-l-l nd the plugPT'is prorided wl ,h may be a iciated 4with any of the multiple jacks J7or lm-thus connecting the signal apparatus to 'relays 538, 39-and 40,The relay 239 actuated by the operation of eitherkey K1 or key K2 andits actuation controls the operation of the generating apparatus 31. Therelay 33 is marginal and is only actuated by the `operation of the keyK1, but is not ac tuated by the operation of the key K2, as the circuitclosed by the operation of the latter key contains the resist-ance 49which serves to so reduce the current that the marginal relay 38 willnot respond. The relay 40 becomes energized when the plug P2 is insertedin the jack J C or the jack J 2.

When the plug P2 is inserted in the jack J G and the plug P, is insertedin one of the jacks J T or J S and the key K2 is operated, the relay 39is actuated and starts the generating apparatus in operation. However asthe relay 38 does not respond upon the operau tion of the key K2 theshunt resistance 35 remains shortcircuited, and,the resistance in theshunt circuit bridged across the outgoing circuit being therebydecreased, the current transmitted to the marginal relay 29 from theapparatus 31 will be less than the current to which it is desired tohave the marginal relay respond. The actuation of the marginal relay 29is indicated byi the functioning of the signal lamp 60. Accordingly ifthe signal lamp 60 functions upon the operation of the key K2 it willindicate that the marginal relay is responding to a current of less thanthe desired st rength and needs adjustment.

The operation of the key Kl serves to energize both relay 39 and relay3S. The en ergization of the latter relay opens the short circuitaffecting the resistance 35 and the increased resistance now in shunt ofthe outgoing circuit of the apparatus 31 causes a current which islgreater and of the desired strength to be transmitted to the marginalrelay 29. If the relay now operates, as will be indicated by the signallamp 60, itis correctly adjusted to respond to a current of the desiredstrength.

The invention may now be more fully understood from the followingdescription of its operation. High frequency ringing current coming inover the line L1 is transmitted to the marginal relay 29 over thefollowing circuit; over conductors which are bridged in shunt of thelines 3 and 4, to the contacts of jack J 2, thence through the windingsof retardation coil 19 and over conductors 'r' and 8 to the tip and ringcontacts of jack J thence over the conductors leading to the tip andring contacts of jack J 6, and thence over conductors 22 and 24 to thewindings of the marginal relay 29. The relay 29 is thereby energized andcauses its armature to pull up and break the following normally closedcircuit; from ground, contact and armature of relay 29, conductor 23,sleeve contact of jack J 6, conductor leading to `sleeve Contact of jackJ 5, conductor 19,

ductors 80 from the conductors 3 and 4 and connecting to the conductors80 a local source 2S of low frequency ringing current suitable tooperate the ringing responsive apparatus at the switchboard.

Vhen the o-perator at the telephone switchboard wishes to send highfrequency ringing current out over the line L1 she applies low frequencyringing current to the conductors 80 at the switchboard. This .lowfrequency current is transmitted over the conductors 3 and 4 as well asthe conductors 5 bridged in shunt thereof to the contacts of jack J2.From thence it is transmitted through the windings of the retardationcoil 19 over conductors 7 and 8 and through the marginal relay 6 whichis bridged in shunt across conductors 7 and 8. The marginal relay 6 isaccordingly energized and pulls up its armature, thereby closing thefollowing circuit; from ground and battery 12., sleeve contact of jackJ2, conductors 13 and 17, armature and contact of relay 6, conductor 15,winding of relay 10 to ground. The actuation of the marginal relay 6also closes the following circuit; from ground and battery 12, sleevecontact of jack J2, conductors 13 and 17, armature and contact of relay6, conductor 15 to connecting point 16, thence o-ver conductor 14, andwinding of relay 1 to ground. The closing of the two above describedcircuits serves to energize relays 1 and 10. The actuation of relay 1serves to disconnect the line L1 from the conductors 3 and 4 and toconnect the line Ll to the conductors 21 leading to the-generatingapparatus 31. The actuation of relay 10 closes a 4circuit from ground,lower armature and contact of relay 10, conductor 20 to the generatingapparatus 31. This starts in operation the apparatus 31 which generatesringing current of a frequency suitable for transmission over the lineL1. This ringing current is transmitted to the line Ll by way of theconductors 21 as formerly ypointed out.

kThe energizationof the relay 10 also serves to close a circuit'fromground, upper armature and contact of relay 10, conductor 18, winding ofrelay 11 to battery and ground. This serves to lock the normallyenergized relay 11, which as has been formerly pointed out becomesde'nergized upon the actuation of the marginal relay 29. Accordingly, inthe event that the marginal relay 29 should become energized by the lowfrequency ringing current generated at the switchboard,

which might happen if it were improperly adjusted, the relay 11 willstill remain energized and prevent the breaking of any of the abovementioned circuits: at the point where the armature of relay 11 is incontact with conductor 13.

As the operation of the second composite set with respect to ringingcurrents transmitted from another transmission line or switchboard issubstantially the saine as t-he operation above described, thedescription of its operation will be omitted.

1n order to test the marginal relay 29 to see if it is properly adjustedto respond only to ringing` current of a frequency similar to that ofthe ringing current transmitted over the line L, the plug P2 is insertedin the jack JG. This serves to close a circuit from ground and bat-tery70, winding of relay 40, conductor 43, sleeve contacts of plug P2 andjack J7, conductor 23, armature and contact of relay 29 to ground. Relay40 is energized over this circuit and disconnects conductor 44 from theconductor leading to the battery 70. The plug P7 is now inserted in thejack J7 and the key K, is operated. This closes the following circuit;from ground and battery 71, windings of relays 38 and 39, conductor 45,tip contacts of jack J7 and plug P7, conductor 46, contacts of key K1,conductor 48, sleeve contact-s of plug P7 and jack J7, to ground. Theclosing of this circuit energizes relays 39 and The actuationv of relay39 causes it to pull up its armature and close a circuit from ground,armature and Contact of relay 39, conductor 72, to the generatingapparatus 31, thereby starting it in operation. rPhe actuation of relay88 causes it to pull up its armature, and thus open the short circuitaround the resista-nce The opening of this short circuit increases thetotal resistance in shunt between the conductors 41 and 42 and allows alarger portion of the current generated by the apparatus 31 to betransmitted outl over the conductors 41 and This current is thentransmitted by way of the tip and ring` contacts of plug P2 and ack J6and over conductors 22 and 24 to the windings of the marginal relay 29.The marginal relay 29 if properly adjusted is accordingly energized andpulls up its armature which serves to break the circuit through relay40, which as has formerly been pointed out. is normally energized uponthe insertion of plug P2 into jack JG. The denergization of relay 40allows its armature to retract and closes the following circuit; fromground and battery 70, contact 73, conductor 44, ring contacts of jack J7 and plug P7, conductor 47, filament of signal lamp 60. conductor 48,sleeve contacts of plug P7 and ack J7, to ground. The closing of thiscircuit causes the signal lamp 60 to glow, thereby indicating that themarginal relay 29 has responded to a current of the desired strength. 1fthe relay does not properly respond to this test it should be adjusteduntil it does.

The key-Kl is now released and the key K2 is operated. This closes thefollowing circuit; from ground and battery 'l' 1, windings of relays 38and 39, conductor 45, tip contacts of jack J 7 and plug P7, conductor46, resistance 49, contacts of key K2, conductor 48, sleeve contacts ofplug P7 and jack J7, to ground. The above described circuit issubstantially similar to the circuit closed when the key K, is operated,except that it includes the additional resist-ance element 49. ri`hisresistance serves to so reduce the current tio-w through the circuitthat. the marginal relay 38 will not respond when the key K2 is operatedand the short circuit about the resistance 35 lwill remain closed. Bythe closing of this circuit however the relay 39 is energized and in thesame manner as formerly pointed out starts the generating apparatus 31into operation. Due to the fact that the short circuit around theresistance 35 remains closed the total resistance in shunt of theconductors 41 and 42 is less than when the key K, was operated andaccordingly the strength of the current transmitted over the conductors41 and 42 from the apparatus 31 is less than the strength of the currenttransmitted thereover upon the operation of the key K1, which currentwas of the value to which it is desired that the relay respond. Thiscurrent is transmitted to the relay 29 in the same manner as the currentsent out from the apparatus 31 upon the operation of key K, and if therelay responds thereto the signal lamp G0 will be caused to glow.Accordingly if the signal lamp glows upon the operation of the key K2 itwill indicate that the relay 29 is responding to a current of less thanthe desired strength, and is in need of adjustment. Adjustment isaccordingly made until the relay no longer responds to the action of keyKg.

1n order to test the marginal relay 8O the plug P2 is inserted in thejack J4. The operation is then substantially the same as when the relay29 is tested and the description of the operation will be omitted.

While the invention has been disclosed as embodied in certain formswhich are considered. desirable, it will be understood that it may beembodied in many widely different organizations without departing fromthe spirit of the invention.

That is claimed is:

1. In a telephone system the combination with a transmission lineleading to a telephone switchboard; of a composite ringing set includingswitching means and a plurality of ringing responsive means, saidswitching means being included in a bridge shunted across saidtransmission line, one of said responsive means responding only toringing current coming in over said transmission line and another ofsaid responsive means responding only to current coming in from saidtelephone switchboard.

2. In a telephone system the combination with a transmission lineleading to a telephone switchboard; of a composite ringing set includingswitching means and a plurality of ringing responsive means, saidswitching means being included in a bridge shunted across saidtransmission line, one of said responsive means responding only toringing current coming in over said transmission line, and means Vundercontrol of said responsive means for associating with the conductorsleading to said telephone switchboard a local source of current suitablefor operating the ringing responsive apparatus at the switchboard,another of said responsive means responsive only to ringing currentgenerated at said switchboard, and means under control of saidresponsive means for associating with the transmission line a. localsource of ringing current suitable for use thereover.

3. ln a telephone system the combination with a transmission line and acomposite ringing set associated therewith including means responsiveonly to ringing current transmitted over said transmission line; of atesting set, a source of current therefor', and means for associatingsaid testing set with said responsive means whereby the currents fromsaid source may be applied to said responsive means.

4. In a telephone system the combination with a transmission line and acomposite ringing set associated therewith including means responsiveonly to ringing current transmitted over said transmission line; of atesting set, a source of current therefor, means for applying currentfrom said source to said responsive means, and controlling means wherebythe amplitude of the current applied from said source to said responsivemeans may be varied, and means to indicate the response of saidresponsive means to said currents.

5. In a telephone system the combination with a transmission line and acomposite ringing set including a marginal relay adjusted to respond toringing current coming in over said transmission line; of an apparatusfor testing the operation of said marginal relay, a source for saidapparatus generating current suitable for transmission over saidtransmission line, means included in the output circuit of said sourcefor simulating said transmission line, a controlling set and means underthe control thereof for varying said simulating means whereby thecurrent transmitted .from said source to said marginal relay may beequal to or less than the strength of the current to which it is desiredto have said marginal relay respond, and means in said controlling setto indicate the response of said marginal relay to the currents fromsaid source.

6. In a telephone system the combination with a plurality oftransmission lines and composite ringing sets associated therewith, saidcomposite sets including means responsive to ringing currentstransmitted over said transmission lines and switching means included inbridges shunted across said transmission lines and associated with saidresponsive means; of a test board at which said switching means may belocated, means at said test board for interconnecting said switchingmeans whereby the responsive means included in one of said compositesets may be substituted for the responsive means of another of saidcomposite sets.

7. In a telephone system the combination with a transmission line; of acomposite ringing set included in a bridge shunted across saidtransmission line, and switching means in said bridge between said lineand said vcomposite set operating to open said bridge and to disconnectsaid composite ringing set from said line when better transmission isdesired thereover. l

8. In a telephone system the combination with a plurality oftransmission lines and composite ringing sets associated therewith, saidcomposite sets being included in bridges shunted across saidtransmission lines and including means responsive to ringing currentstransmitted over said transmission lines; of switching means in saidbridges whereby the responsive means included in one of said compositesets may be substituted for the responsive means of another of saidcomposite sets.

In testimony whereof I have signed my name to this specication, in thepresence of two subscribing witnesses, this 24th day of October, 1917.

JOHN F. TOOMEY. Witnesses:

ALFRED KAUFMANN, MARY A. ROGERS.

Copies of this patent may be obtained for ve cents each, by addressingthe Gommssioncr of Patents, Washington, D. C.

